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| Titel |
Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere |
| VerfasserIn |
S. Becker, C. J. Halsall, W. Tych, R. Kallenborn, M. Schlabach, S. Manø |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 9 ; Nr. 12, no. 9 (2012-05-08), S.4033-4044 |
| Datensatznummer |
250011118
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| Publikation (Nr.) |
 copernicus.org/acp-12-4033-2012.pdf |
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| Zusammenfassung |
| An extensive database of organochlorine (OC) pesticide concentrations
measured at the Norwegian Arctic monitoring station at Ny-Ålesund,
Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere.
Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and
cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to
isolate underlying inter-annual trends. Although a simple comparison of
annual mean concentrations (1994–2005) suggest a decline for all of the OCs
investigated, the longer-term trends identified by DHR only show a
significant decline for p,p'-DDT. Indeed, HCB shows an increase from
2003–2005. This is thought to be due to changes in source types and the
presence of impurities in current use pesticides, together with retreating
sea ice affecting air-water exchange. Changes in source types were revealed
by using isomeric ratios for the chlordanes and DDTs. Declining trends in
ratios of trans-chlordane/cis-chlordane (TC/CC) indicate a
shift from primary sources, to more "weathered" secondary sources, whereas
an increasing trend in o,p'-DDT/p,p'-DDT ratios indicate a shift from use
of technical DDT to dicofol. Continued monitoring of these OC pesticides is
required to fully understand the influence of a changing climate on the
behaviour and environmental cycling of these chemicals in the Arctic as well
as possible impacts from "new" sources. |
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